Heat trap assembly

ABSTRACT

An outlet heat trap assembly for a tank-type water heater includes a tube having a tube wall, the tube defining a bore extending along a longitudinal axis and a transverse opening through the tube wall, the transverse opening communicating with the bore; and a flexible member within the bore, the flexible member deflectable between a first position in which the flexible member covers the transverse opening, and a second position in which the flexible member is deflected toward the longitudinal axis to allow fluid flow through the transverse opening into the bore. The outlet heat trap assembly further comprises an insert member coupled to a distal end of the tube, wherein the tube further defines an axial opening at the distal end of the tube, the axial opening communicating with the bore, and wherein the insert member covers the axial opening.

BACKGROUND

The present invention relates to a convection heat trap assembly for a tank-type water heater to reduce energy loss during standby, and more specifically to a convection heat trap assembly for a hot water outlet.

SUMMARY

In one embodiment, the invention provides a heat trap assembly for a water heater provided at a hot water outlet of the water heater to reduce heat loss during standby.

One aspect, the invention provides an outlet heat trap assembly, comprising: a tube having a tube wall, the tube defining a bore extending along a longitudinal axis and a transverse opening through the tube wall, the transverse opening communicating with the bore; and a flexible member within the bore, the flexible member deflectable between a first position in which the flexible member covers the transverse opening, and a second position in which the flexible member is deflected toward the longitudinal axis to allow fluid flow through the transverse opening into the bore. In some aspects of the invention the outlet heat trap assembly further comprises an insert member coupled to a distal end of the tube, wherein the tube further defines an axial opening at the distal end of the tube, the axial opening communicating with the bore, and wherein the insert member covers the axial opening. In some aspects of the invention, the insert member includes a body portion received by the bore via the axial opening at the distal end of the tube. In some aspects of the invention, the body portion has a first end, and wherein the flexible member bends towards the longitudinal axis about the first end of the body portion. In some aspects of the invention, the insert member includes protrusions extending from a body portion of the insert member transverse to the longitudinal axis to provide a friction fit between the insert member and the tube. In some aspects of the invention, the transverse opening comprises a plurality of transverse openings, wherein the flexible member comprises a plurality of flexible members, and wherein the sum of the plurality of transverse openings equals the sum of the plurality of flexible members.

In another aspect of the invention, the invention provides an outlet heat trap assembly, comprising: a tube having a tube wall, the tube defining a bore extending along a longitudinal axis and a transverse opening through the tube wall, the transverse opening communicating with the bore; an insert member coupled to the distal end of the tube to cover the axial opening; and a flexible member within the bore, the flexible member deflectable between a first position in which the flexible member covers the transverse opening, and a second position in which the flexible member is deflected toward the longitudinal axis to allow fluid flow through the transverse opening into the bore. In some aspects of the invention, the insert member includes a body portion received by the bore via the axial opening at the distal end of the tube. In some aspects of the invention, the body portion has a first end, and wherein the flexible member bends towards the longitudinal axis about the first end of the body portion. In some aspects of the invention, the insert member includes protrusions extending from a body portion of the insert member transverse to the longitudinal axis to provide a friction fit between the insert member and the tube. In some aspects of the invention, the transverse opening comprises a plurality of transverse openings, wherein the flexible member comprises a plurality of flexible members, and wherein the sum of the plurality of transverse openings equals the sum of the plurality of flexible members.

In another aspect, the invention provides a method for reducing energy loss during standby in a water heater, comprising: providing a water heater including a tank defining an interior space adapted to contain water, a heat source operable to heat the water within the tank, a cold water inlet in fluid communication with the interior space, the cold water inlet adapted to deliver cold water to the interior space from a cold water source, a hot water outlet, and a heat trap assembly coupled to the hot water outlet, the heat trap assembly having a tube having a tube wall, the tube defining a bore extending along a longitudinal axis and a transverse opening through the tube wall, the transverse opening communicating with the bore; and a flexible member within the bore, the flexible member deflectable between a first position in which the flexible member covers the transverse opening, and a second position in which the flexible member is deflected toward the longitudinal axis to allow fluid flow through the transverse opening into the bore; during standby, covering the transverse opening by the flexible member, sealing the transverse opening from fluid flowing into the bore; and during performance draw, deflecting the second end of the flexible member toward the longitudinal axis to allow fluid flow through the transverse opening into the bore.

Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a tank-type water heater including a water outlet heat trap assembly embodying the invention.

FIG. 2 is a perspective view of the water outlet heat trap assembly of FIG. 1.

FIG. 3 is an exploded view of the water outlet heat trap assembly of FIG. 2.

FIG. 4 is a partially exploded view of the water outlet heat trap assembly of FIG. 2.

FIG. 5 is a cross-sectional view of the water outlet heat trap assembly of FIG. 2 illustrating deflectors in an initial position.

FIG. 6 is a cross-sectional view of the water outlet heat trap assembly of FIG. 2 illustrating the deflectors in a deflected position.

FIG. 7 is a schematic view of another configuration for a tank-type water heater including the water outlet heat trap assembly.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

With reference to FIG. 1, a tank-type water heater 110 includes a tank 120 defining an interior space 130 for holding water, insulation 140 around the tank 120 to reduce heat loss, a heat source 150 for heating the water in interior space 130, an inlet spud 160, a dip tube 170 extending into the interior space 130, an outlet spud 180, and an outlet heat trap assembly 190 extending into the interior space 130.

The heat source 150 is shown schematically in FIG. 1 and is intended to include a gas-fired burner in a combustion chamber with one or more flues extending through the interior space 130, one or more electric heating elements, the condenser of a heat pump, waste heat from another device, or any other device for generating heat and transferring the heat to the water in the tank 120. Embodiments of the present invention can include any combination of the example heat sources provided above, combined with each other or with any other suitable devices used as the heat source 150.

The tank 120 includes an upper head 210 that is dome-shaped with a concave side 220 facing into the interior space 130. The inlet spud 160 and outlet spud 180 are welded or otherwise permanently affixed to the upper head 210. Each surrounds a hole (i.e., a cold water inlet and a hot water outlet) in the upper head 210 and includes interior threads. The tank 120 and interior space 130 include an upper portion 230 (a top boundary of which is defined by the concave surface 220) and a lower portion 240. During ordinary operation of the water heater 110, water can only enter and exit the interior space 130 via the inlet spud 160 and outlet spud 180. Other openings in the tank 120 (including but not limited to a drain, a temperature and pressure (T&P) relief valve spud, an anode spud, and an electric heating element spud or gas valve spud) are water-tightly closed during ordinary operation.

A cold water supply pipe 260 communicates between a source of cold water 270 and the inlet spud 160 through the inlet side pipe nipple 250. A hot water pipe 280 communicates between a hot water access point or point-of-use 290 and the outlet spud 180 through the outlet tube heat trap assembly 190. The dip tube 170 and the outlet tube heat trap assembly 190 are sealed with respect to the respective cold water and hot water pipes 260, 280 such that during ordinary operation of the water heater 110, water can only flow into and out of the interior space 130 through the dip tube 170 and outlet tube heat trap assembly 190, respectively.

The dip tube 170 is illustrated in FIG. 1 as a relatively simple open-ended tube, with one or more axial openings (i.e., openings that permit flow parallel to the longitudinal axis of the dip tube 170). Other embodiments of the dip tube 170 may include transverse openings (i.e., openings that permit flow perpendicular to the respective longitudinal axes) or a combination of axial and transverse openings. In the configuration illustrated in FIG. 1, the dip tube 170 and the outlet heat trap assembly 190 are vertically oriented (i.e., the longitudinal axes are vertical). With the axial openings of the dip tube 170 in FIG. 1, flow is directed vertically (down from the dip tube 170 and up to the outlet heat trap assembly 190).

The hot water access point or point-of-use 290 may be, for example, a faucet or a water-consuming appliance. Cold water is supplied at supply pressure (usually around 30 psi but sometimes as high as 60 psi) from the cold water source 270 (e.g., a water utility or well pump) through the cold water pipe 260. When the access point 290 is opened, the hot water pipe 280 is exposed to atmospheric pressure, which permits cold water to flow at supply pressure into the lower portion 240 of the tank 120 via the dip tube 170 and displace hot water from the upper portion 230 of the tank 120 via the outlet heat trap assembly 190 and hot water pipe 280. During standby (i.e., between hot water draws, when the access point 290 is closed), the heat source 150 heats the water in the tank 120 that has been cooled by introduction of cold water into the lower portion 240.

The term “cold water inlet” is intended to cover any other components that are used in a particular embodiment in the delivery of cold water to the interior space 130. In the illustrated embodiment, the cold water inlet includes the inlet spud 160, the dip tube 170, and the pipe nipple 250, but one should not read the term as limited to or requiring those particular elements.

FIGS. 2-4 illustrate the outlet heat trap assembly 190, which includes an outlet tube 300, a pipe nipple 304, and a deflector insert assembly 308. The outlet tube 300 extends along a longitudinal axis 312 and defines a bore 316 extending through the outlet tube 300 from a first, distal end 320 to a second, proximal end 324. A first length of the outlet tube 300 is positioned within the pipe nipple 304 concentric with the longitudinal axis 312. The outlet tube 300 is typically made of a polymer and acts as a liner for the pipe nipple 304. In the illustrated embodiment, the outlet tube 300 is mechanically connected with the pipe nipple 304 by an annular swedge 340, crimp, or the like, to deform the pipe nipple 304 radially inward toward the outlet tube 300. The annular swedge 340 also provides a seal between the pipe nipple 304 and the outlet tube 300. A second length of the outlet tube 300 extends from the pipe nipple 304 to the first end 320. The outlet tube 300 is provided with laterally-facing or transverse openings 344 (i.e., openings permitting flow perpendicular to the longitudinal axis 312 of the outlet tube 300) which communicate through the tube wall with the bore 316 of the outlet tube 300. The transverse openings 344 are provided on the second length of the outlet tube 300. In the illustrated embodiment, there are two transverse openings 344 circumferentially spaced about the longitudinal axis 312 of the outlet tube 300 and on opposite sides of the longitudinal axis 312 of the outlet tube 300. In some embodiments, there may be any number of transverse openings 344 and they may or may not be evenly spaced about the longitudinal axis 312 of the outlet tube 300.

In the illustrated embodiment, the outlet tube 300 is cylindrical and the bore 316 has a circular cross-sectional shape. In other embodiments, the bore 316 may have another cross-sectional shape.

In the illustrated embodiment, the pipe nipple 304 has a first threaded end 350 and a second threaded end 354. The first threaded end 350 is threaded into the outlet spud 180 once the outlet tube 300 has been inserted into the interior space 130 through the outlet spud 180 to connect the outlet heat trap assembly 190 to the tank 120 (see FIG. 1). The second threaded end 354 of the pipe nipple 304 threads into the hot water pipe 280. In some embodiments, in lieu of the annular swedge 340, the second end 324 of the outlet tube 300 may have a flange that is positioned between the second threaded end 354 and the outlet tube 300 to secure the outlet tube 300 in place. In such embodiments, the flange may provide a seal between the pipe nipple 304 and the outlet tube 300.

With continued reference to FIGS. 2-4, the deflector insert assembly 308 includes a rigid insert member 360 and flexible deflectors 364 each corresponding to one of the transverse openings 344. The rigid insert member 360 includes a body portion 370 and a cap portion 374 positioned at a proximal end 406 of the body portion 370. The body portion 370 has an outer diameter less than an inner diameter of the bore 316 of the outlet tube 300 so as to be received by an axial opening 378 at the first end 320 of the outlet tube 300 in the bore 316. The cap portion 374 overhangs the body portion 370 around its circumference and has a diameter generally larger than the diameter of the body portion 370 and the outlet tube 300. When the rigid insert member 360 is installed in the bore 316, the overhanging rim of the cap portion 374 covers the bore 316. The overhanging rim of the cap portion 374 abuts the first end 320 of the of the outlet tube 300 such that further axial movement of the insert member 360 into the bore 316 is inhibited and the insert member 360 is properly positioned within the bore 316. In the illustrated embodiment, a plurality of raised ribs 382 extend radially outward from the body portion 370 of the insert member 360 and provide a friction fit within the bore 316 to secure the insert member 360 to the outlet tube 300. In some embodiments, the ribs 382 may be replaced with protrusions of any shape. In further embodiments, the insert member 360 is coupled to the outlet tube 300 in another similar way (e.g., snap-fit, fasteners, etc.). When the insert member 360 is received in the first end 320 (see FIG. 2) of the outlet tube 300, the insert member 360 closes off the axial opening 378 at the first end 320 of the outlet tube 300 so that there is no fluid flow into or out of the outlet tube 300 through the axial opening 378 at the first end 320 of the outlet tube 300.

Each deflector 364 has a proximal end portion 386 fixed relative to the outlet tube 300 and a distal end portion 390 free to deflect radially inward relative to the longitudinal axis 312 of the outlet tube 300. The body portion 370 defines recesses 394 each corresponding to one of the deflectors 364. In the illustrated embodiment, there are two recesses 394 that are circumferentially spaced apart about the longitudinal axis 312 and positioned on opposite sides of the longitudinal axis 312. Each recess 394 sweeps an arc having a width corresponding to the width of the proximal end portion 386 of the deflector 364. Each deflector 364 is received in one of the recesses 394 (see FIG. 3) and is pressed between the body portion 370 of the insert member 360 and the outlet tube 300 when the body portion 370 is received in the bore 316 of the outlet tube 300.

In the illustrated embodiment, a projection 398 extends from the body portion 370 of the insert member 360 within each of the recesses 394. Each deflector 364 defines an aperture 402 in the proximal end portion 386 that receives the projection 398, as best shown in FIG. 3, to couple the proximal end 386 of the deflector 364 to the insert member 360. Accordingly, when the insert member 360 is inserted in the first end 320 of the outlet tube 300, the projection 398 inhibits axial movement of the proximal end portion 386 of the deflector 364. Furthermore, radial movement of the proximal end portion 386 of the deflector 364 is inhibited due to the proximal end portion 386 of the deflector 364 pressed between the body portion 370 of the insert member 360 and the outlet tube 300, as discussed above. In some embodiments, the deflector 364 may be thermoplastic staked or heat staked to the projection 398.

The deflectors 364, fixed between the body portion 370 of the insert member 360 and the outlet tube 300, are flexible such that the deflectors 364 may generally bend at the distal end portion 390, opposite the fixed end (i.e. the proximal end portion 386 of the deflector 364), when outside forces are applied. Furthermore, a distal end 410 of the body portion 370 becomes a hinge point at which the deflectors 364 may bend radially inward, relative to the longitudinal axis 312 of outlet tube 300, when outside forces are applied. The deflectors 364 are further resilient such that the deflectors 364 can revert to their original position when no outside forces are being applied, as discussed below.

As best shown in FIGS. 5-6, the distal end portion 390 of each deflector 364 may move or deflect from a first, initial, or undeflected position to a second, deflected position. In the first position (FIG. 5), the distal end portion 390 of the deflector 364 extends axially across the transverse opening 344 to cover and seal the transverse opening 344 of the outlet tube 300 from fluid communication with the bore 316. In the second position (FIG. 6), the distal end portion 390 of the deflector 364 deflects radially inward such that the transverse opening 344 are uncovered, allowing fluid communication with the bore 316. In other words, the deflectors 364 may act as a leaf spring coupled at one end (i.e. the proximal end portion 386) in which the free end (i.e. distal end portion 390) moves, or deflects from the first position to the second position or from the second position to the first position. Furthermore, the deflectors 364 are biased toward the first position due to the resilience, or springiness, of the deflectors 364 and may “spring back”, or revert back to the first position when no outside forces are being applied.

In operation of the water heater 110, during standby, the distal end portion 390 of each of the deflectors 364 is in the first position (FIG. 5) to cover the transverse openings 344. The deflectors 364 seal the transverse openings 344 and resist hot water in the top portion 230 of the interior space 130 of the tank 120 from flowing through the transverse openings 344 into the outlet tube 300 and the hot water pipe 280 under natural convection. The deflectors 364 thereby inhibit standby convection heat loss through the outlet tube 300, the pipe nipple 304, and the hot water pipe 280.

During a performance draw (i.e., when the access point 260 is opened), a vacuum pulls on the deflectors 364, causing the distal end portions 390 of each deflector 364 to deflect radially inward toward the longitudinal axis 312 of the outlet tube 300 in the second position (FIG. 6). As such, the transverse openings 344 are uncovered, allowing hot water in the top portion 230 of the interior space 130 to be displaced and flow through the transverse openings 344 into the outlet tube 300 and to the access point 260 via the hot water pipe 280, as the cold water enters the tank 120 via the dip tube 170. In the illustrated embodiment, a total fluid flow area defined by the transverse openings 344 is greater than the cross-sectional flow area of the bore 316. Accordingly, using outlet heat trap assemblies having deflectors 364 positioned in the outlet tube 300 does not restrict the size of the diameter (i.e. bore 316) of the outlet tube 300. Moreover, know outlet heat trap assemblies positioned in the pipe nipple are commonly affected by pressure drops due to the need to reduce the diameter of the outlet tube 300 (i.e. placement of a heat trap assembly in the pipe nipple inherently reduces the diameter). Using outlet heat trap assemblies having deflectors 364 positioned in the outlet tube 300 are advantageous over these systems such that they do not restrict the size of the diameter that can cause the pressure drop through the hot water outlet tube 300.

As shown in FIG. 1, the outlet heat trap assembly 190 is installed in the water heater 110 with the longitudinal axis 312 of the outlet tube 300 vertical. In such a configuration, the transverse openings 344 draw water into the outlet tube horizontally.

FIG. 7 illustrates another configuration of the water heater 110, having all the same components as shown in FIG. 1, but with the outlet tube 300 of the heat trap assembly 190 of FIGS. 2-6 extending horizontally into the interior space 130 through a sidewall of the tank 120. In this configuration, the outlet tube 300 does not extend through the concave side 220 of the upper head 210, but instead extends under the concave side 220 of the upper head 210 in the top portion 230. In addition to disposing the outlet tube vertically (FIG. 1) and horizontally (FIG. 7) any non-vertical and non-horizontal angle is permissible within the intent of this invention. Also, for a horizontally-extending or angled outlet tube 300, one can rotate the outlet tube 300 about its longitudinal axis 312 to position the transverse openings 344 horizontally, vertically, or at an angle in between horizontal and vertical.

Thus, the invention provides, among other things, an outlet heat trap assembly for a water heater to reduce heat loss during standby. Various features and advantages of the invention are set forth in the following claims. 

1. An outlet heat trap assembly provided at a hot water outlet of a tank-type water heater, comprising: a tube having a tube wall, the tube defining a bore extending along a longitudinal axis and a transverse opening through the tube wall, the transverse opening communicating with the bore; and a flexible member within the bore, the flexible member deflectable between a first position in which the flexible member covers the transverse opening, and a second position in which the flexible member is deflected toward the longitudinal axis to allow fluid flow through the transverse opening into the bore.
 2. The outlet heat trap assembly of claim 1, further comprising an insert member coupled to a distal end of the tube, wherein the tube further defines an axial opening at the distal end of the tube, the axial opening communicating with the bore, and wherein the insert member covers the axial opening.
 3. The outlet heat trap assembly of claim 2, wherein a first end of the flexible member is coupled to the insert member.
 4. The outlet heat trap assembly of claim 2, wherein the insert member includes a body portion received by the bore via the axial opening at the distal end of the tube.
 5. The outlet heat trap assembly of claim 4, wherein the body portion has a first end, and wherein the flexible member bends towards the longitudinal axis about the first end of the body portion.
 6. The outlet heat trap assembly of claim 2, wherein the insert member includes protrusions extending from a body portion of the insert member transverse to the longitudinal axis to provide a friction fit between the insert member and the tube.
 7. The outlet heat trap assembly of claim 1, wherein the flexible member extends parallel to the longitudinal axis.
 8. The outlet heat trap assembly of claim 1, wherein the transverse opening comprises a plurality of transverse openings, wherein the flexible member comprises a plurality of flexible members, and wherein the number of the plurality of transverse openings equals the number of the plurality of flexible members.
 9. The outlet heat trap assembly of claim 8, wherein the plurality of transverse openings comprises a first transverse opening and a second transverse opening circumferentially spaced from the first transverse opening about the longitudinal axis of the outlet tube, and wherein the first transverse opening and the second transverse opening are on opposite sides of the longitudinal axis.
 10. The outlet heat trap assembly of claim 8, wherein a sum of area of the plurality of transverse openings define a total inlet fluid flow cross-sectional area greater than an inner fluid flow cross-sectional area of the bore in a plane transverse to the longitudinal axis.
 11. An outlet heat trap assembly provided at a hot water outlet of a tank-type water heater, comprising: a tube having a tube wall and a distal end, the tube defining a bore extending along a longitudinal axis and an axial opening at the distal end of the tube, the axial opening communicating with the bore, the tube wall defining a transverse opening through the tube wall, the transverse opening communicating with the bore; an insert member coupled to the distal end of the tube to cover the axial opening; and a flexible member within the bore, a first end of the flexible member coupled to the insert member, the flexible member deflectable between a first position in which the flexible member covers the transverse opening, and a second position in which the flexible member is deflected toward the longitudinal axis to allow fluid flow through the transverse opening into the bore.
 12. The outlet heat trap assembly of claim 11, wherein a first portion of the flexible member defines an aperture, and wherein the insert member includes a projection received in the aperture to couple the first end to the insert member.
 13. The outlet heat trap assembly of claim 11, wherein the insert member includes a body portion received by the bore via the axial opening at the distal end of the tube.
 14. The outlet heat trap assembly of claim 13, wherein the body portion has a first end, and wherein the flexible member bends towards the longitudinal axis about the first end of the body portion.
 15. The outlet heat trap assembly of claim 11, wherein the insert member includes protrusions extending from a body portion transverse to the longitudinal axis to provide a friction fit between the insert member and the tube.
 16. The outlet heat trap assembly of claim 11, wherein the flexible member extends parallel to the longitudinal axis.
 17. The outlet heat trap assembly of claim 11, wherein the transverse opening comprises a plurality of transverse openings, wherein the flexible member comprises a plurality of flexible members, and wherein the number of the plurality of transverse openings equals the number of the plurality of flexible members.
 18. A method for reducing energy loss during standby in a water heater, comprising: providing a water heater including a tank defining an interior space adapted to contain water, a heat source operable to heat the water within the tank, a cold water inlet in fluid communication with the interior space, the cold water inlet adapted to deliver cold water to the interior space from a cold water source, a hot water outlet, and a heat trap assembly coupled to the hot water outlet, the heat trap assembly having a tube having a tube wall, the tube defining a bore extending along a longitudinal axis and a transverse opening through the tube wall, the transverse opening communicating with the bore; and a flexible member within the bore, the flexible member deflectable between a first position in which the flexible member covers the transverse opening, and a second position in which the flexible member is deflected toward the longitudinal axis to allow fluid flow through the transverse opening into the bore; during standby, covering the transverse opening by the flexible member, sealing the transverse opening from fluid flowing into the bore; and during performance draw, deflecting the second end of the flexible member toward the longitudinal axis to allow fluid flow through the transverse opening into the bore.
 19. The method of claim 18, the heat trap assembly further comprising an insert member coupled to a distal end of the tube, wherein the tube further defines an axial opening at the distal end of the tube, the axial opening communicating with the bore, and wherein the insert member covers the axial opening.
 20. The method of claim 18, wherein the flexible member is coupled to the insert member, wherein the insert member includes a body portion having a first end, and wherein the flexible member bends towards the longitudinal axis about the first end of the body portion. 